Quality indicators and technique for analyzing permanent I-125 prostate seed implants: Seven years postimplant dosimetry evaluation

Abstract

CT-based PID was found less reliable than US-CT fusion-based PID due to target volume overestimation. This result shows the biased interpretation of low D90 values based on CT-based targeting, providing unreliable correlations between D90 and relapse probability. The low urinary retention statistics are in accordance with the PID data for the organ, as only 5.2% of patients had their PID D10 > 218 Gy, i.e., above the recommended GEC-ESTRO guidelines. Besides the "learning" component, the PID D90 curve is influenced by the PID technique.

Sector analysis provides additional spatial information on the permanent prostate brachytherapy learning curve

“…A global dosimetric learning curve has been widely reported for PPB and is characterized by improving postimplant dosimetry (PID) indices such as the D 90 (dose delivered to 90% of the prostate volume) (8,9) and improving patient-reported outcome measures (PROMs) (10,11). Feedback from global PID is a valuable learning tool, particularly for new centers, allowing the implanting team to identify trends and adjust both their planning and implant techniques (12).…”

Technical and dosimetric aspects of iodine-125 seed reimplantation in suboptimal prostate implants

“…As described in the study by Marcu et al [7], the PID CT images are coregistered (matched) to the pre-implant ultrasound images, with the image fusion module of the SPOT-PRO treatment planning system, by manually shifting and rotating the overlaid image sets until anatomical references are aligned. Once image sets are matched, the target and PTV from the ultrasound images are copied onto the CT images; the rectum and urethra are drawn directly onto the CT images.…”

“…The decision to undergo reimplantation was based on the PID results using ultrasound-CT image coregistration, which our centre's standard technique (the methods are described in detail in a previous report [7]). However, in all situations, the main dosimetric parameters were independently confirmed by a second medical physicist, and in some cases, when the result was uncertain, an alternative PID technique was also used, such as CT-delineation-based PID or MR-CT image coregistration-based PID.…”

Treatment technique evolution and dosimetry trends over seven years of low dose rate prostate brachytherapy at an Australian institution

“…The aim of the current work was to illustrate the evolution of the LDR implant techniques over a 7-year time period and to assess the effect of these different techniques on both logistics and clinical input. While post implant dosimetry (PID) is an important component of the LDR treatment process, the effect of the treatment technique on PID is not presented here as it was discussed in previous reports [3,4]. The current paper focuses on the dosimetric evolution of implants from a treatment planning perspective rather than a post implant evaluation.…”